通用陆面模型CLM3.0在冬小麦-夏玉米农田的参数化方案改进——以海河平原的3个试验站为例

Improved parameterization schemes of winter wheat-summer maize land model:Three experiment stations in Haihe river plain for example

为了准确模拟冬小麦-夏玉米种植制度下的农田土壤墒情,本研究改进通用陆面模型CLM3.0的参数化方案,包括灌溉措施及作物种植制度参数化的加入、土壤厚度及土壤层的剖分修改、作物水文及土壤水文过程的一些参数化修改、考虑作物的株高变化等,在海河平原的3个农业观测试验站(东北旺、栾城、洪门)验证改进后的模型的适用性。结果表明:改进后的CLM3.0模型在冬小麦和夏玉米种植制度下的农田具有较好的适用性,可以抓住各层土壤湿度的变化,与改进前的模型相比,其土壤墒情模拟精度明显提高,2m土体土壤湿度的均方根误差在东北旺、栾城和洪门试验站分别减少了45.2%、47.1%和51.5%。

Land surface model provides with a good way for monitoring regional farmland soil moisture. The improved parameterization scheme of winter wheat-summer maize farmlands in the model is critical for accurately simulating soil moisture of the agricultural regions. This study focuses on prediction of soil moisture and presents the improved solutions. In particular, we incorporated the parameterizations of irrigation and winter wheat-summer maize cropping regimes, reselected total soil depth and the depths of the nodes of the different soil layers, modified the vegetation and soil hydrology parameterizations and replaced the invariant parameters of canopy top and bottom heights with crop morphological data. Subsequently, to assess the performance of these modifications, a set of offline simulations were carried out at three agricultural experiment stations （Dongbeiwang/Luancheng/Hongmen） in Haihe river plain. The results showed that the improved CLM3.0 model had better applicability in winter wheat-summer maize cropland, and could capture well the major characteristics of the observed total variations of soil moisture. In comparison with simulated soil moisture before model improvements, the root mean square errors decreased by 45.2% ,47. 1% and 51.5% at Dongbeiwang,Luancheng and Hongmen Experiment Stations respectively.